RHEL 9 must not have unauthorized IP tunnels configured.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-257950	SRG-OS-000480-GPOS-00227	RHEL-09-252045	SV-257950r1045006_rule	2025-02-27	2

Description
IP tunneling mechanisms can be used to bypass network filtering. If tunneling is required, it must be documented with the information system security officer (ISSO).

ℹ️ Check
Verify that RHEL 9 does not have unauthorized IP tunnels configured. Determine if the "IPsec" service is active with the following command: $ systemctl is-active ipsec Inactive If the "IPsec" service is active, check for configured IPsec connections ("conn"), with the following command: $ sudo grep -rni conn /etc/ipsec.conf /etc/ipsec.d/ Verify any returned results are documented with the ISSO. If the IPsec tunnels are active and not approved, this is a finding.

ℹ️ Check

Verify that RHEL 9 does not have unauthorized IP tunnels configured. Determine if the "IPsec" service is active with the following command: $ systemctl is-active ipsec Inactive If the "IPsec" service is active, check for configured IPsec connections ("conn"), with the following command: $ sudo grep -rni conn /etc/ipsec.conf /etc/ipsec.d/ Verify any returned results are documented with the ISSO. If the IPsec tunnels are active and not approved, this is a finding.

✔️ Fix
Remove all unapproved tunnels from the system, or document them with the ISSO.